iBook and PowerBook G4 owners/users are strongly advised to check your batteries against the list of affected batteries. Apple has determined that certain lithium-ion batteries containing cells manufactured by Sony Corporation of Japan pose a safety risk that may result in overheating under rare circumstances.
The affected batteries were sold worldwide from October 2003 through August 2006 for use with the following notebook computers: 12-inch iBook G4, 12-inch PowerBook G4 and 15-inch PowerBook G4. Please refer attached list:
Although there does not seem to be a close out date for replacements, its recommended that the replacement be carried out expediently. Note that replacement batteries will only be shipped upon receipt of faulty batteries. Otherwise, the other option is to head down to your local Apple Service Centre and submit your battery manually in lieu of shipping.
Read more at Apple’s Battery Exchange Program iBook G4 and PowerBook G4 page.